Genuinely my favourite show of all time. Narrowing it down to a single favourite episode is tough, though.

If ever I introduce someone to Red Dwarf, because they've either never heard of it or just never seen it, I'll often show them Gunmen of the Apocalypse. Emmy award winning episode, and rightfully so. So much plot is put into less than 30 minutes of show time, and it is executed to perfection.